The Facetmobile is a Low Aspect Ratio Lifting Body Experimental Homebuilt
Airplane. It is stall-resistant, easy to construct, and voluminous.

FACETMOBILE FMX-4 RESEARCH AIRPLANE

The Facetmobile is an experimental lifting-body sport airplane.
It was built by Barnaby Wainfan, Rick Dean, and Lynne Wainfan to explore the
characteristics and potential of this type of airplane. The configuration was developed using a combination of analytical
methods, radio-controlled model testing and wind-tunnel testing. In all, 8
radio-controlled models were built and flown. Construction of N117WD took 2 1/2
years. First flight was April 22, 1993. Total flight time to date is
approximately 130 hours. No plans or kits are currently being offered.

In
1994, the airplane was flown to Oshkosh, WI from Chino, California and back. On
the outbound flight it covered 2,253 miles in a total air time of 25 hours and
46 minutes.

On Oct. 13, 1995, while enroute to the Copperstate Fly-in, the
Facetmobile experienced an in-flight loss of power due to a carburetor
malfunction, and Barnaby was forced to make a dead-stick landing. He was unable
to avoid a barbed-wire fence, and hit it at approximately 30 knots. The airplane
was damaged, but Barnaby was not. N117WD is currently being repaired, and will
fly again .

The
FMX-4 flight test program conclusively demonstrated that the low-aspect-ratio,
faceted, tailless configuration is viable for a light general aviation airplane.
The overall performance of the airplane compared well with the performance of
conventionally-configured airplanes using the same power plant.The airplane demonstrated the ability to carry a useful load equal to its
empty weight.

The
flying qualities of the FMX-4 are benign and conventional.Control forces are linear, and well harmonized. The airplanes motions are
well damped about all axes. Very little rudder is required to coordinate turns
in up-and-away flight.

In
the approach configuration, the airplane has a strongly stable dihedral effect.
Dutch roll is well damped, so the primary effect of the strong lateral stability
is the need for significant lateral stick force to maintain a steady-state
sideslip during a crosswind approach.

The
airplane is highly departure resistant at high angles of attack.The airplane did not have angle of attack instrumentation, but wind
tunnel results indicate that full aft stick should trim the airplane to
approximately 30 degrees angle of attack. In flight test, in the full-aft-stick
condition, the airplane exhibited a moderate high-frequency aerodynamic buffet,
and a power-off sink rate of about 1000 feet per minute. Roll damping remained
stable, and the airplane exhibited no tendency to roll off or depart, even
during gentle lateral maneuvering. The controls remained effective about all
axes.

The
aircraft was not equipped with a flying pitot head. Accordingly, the true
minimum aispeed could not be measured because the fixed pitot tube stalled at
high AOA, leading to an airspeed reading of zero on the airspeed indicator
before buffet onset. Wind tunnel data predicts that the steady-state airspeed at
the angle of attack for maximum lift is approximately 33 knots.

These
flight test results, as well as results of more aggressive high angle of attack
investigations conducted with the ¼ scale radio-controlled model indicate that
the FMX-4 is highly spin resistant and will not be prone to the typical
stall/spin accident seen with conventional airplanes.

The
FMX-4 test program demonstrated that the configuration offers many advantages as
a personal air vehicle. The primary advantages demonstrated are:

FACETMOBILE FMX-5 PROJECT

The FMX-5 is our vision of a personal airplane using the
concepts pioneered by the Facetmobile. The project is currently dormant,
since we do not have the resources to complete the restoration of the
Facetmobile N117WD and build a new prototype at the same time. We are continuing
to do extensive engineering work to refine the design. The FMX-5 project
remains a concept. We are still working on the design, refining it, and
optimizing it to fit into the new “Light Sport” aircraft category. FMX-5 is
evolving into SPORT FACET.

Once the restoration of FMX-4 is complete, SPORT FACETwill be our next priority project.We
are interested to hear from individuals or organizations with the resources to
help make this exciting new airplane a reality

A MULTI-FACETED OPPORTUNITY!We are
interested in talking to individuals or groups who want to help make the FMX-5
SPORT FACET a
reality faster than we can do it ourselves. Up to now the project has proceeded
as a homebuilt project. It is happening only as fast our available time and money will
allow. Although we will continue this effort, we are receptive to other
approaches to moving the FMX-5 ahead. A focused, well financed effort can have
a prototype flying much sooner, and lead to early kit production. If you
have the resources to help make FMX-5 a reality, and want to be a part of a
whole new facet of aviation please contact us.You can reach us by e-mail at:
Facetmobile@Yahoo.com

The FMX-5 is a new
aircraft design based on the Facetmobile FMX-4 (N117WD). The FMX-5 design is a
2-seater projected to use engines in the 100 to 150 horsepower class. It is not simply a scaled-up Facetmobile, but incorporates many improvements based
on what we have learned in 130 hours of flying N117WD. The prototype will be
powered by either a Lycoming O-235 or the new Jabiru 6-cylinder engine, and the
structure will be stressed to handle engines up to 150 hp, including the
Lycoming 0-320. The baseline structure of the FMX-5 is similar to the FMX-4: a mix of steel tube, aluminum
tube, and sheet aluminum covered with fabric.

We are also investigating
an alternative version composed of flat composite sandwich panels. The composite flat-panel
design is suitable for highly automated manufacturing using numerically
controlled cutters (water jet or laser) to cut out the panels. The panels are
designed to interlock so that the structure will be self-aligning and require a
minimum of jigging for assembly.

We want to
offer FMX-5 as a kit once the prototype has satisfactorily complete flight
testing.

A major advantage of the low aspect ratio lifting body configuration is
the large useful volume inside the airplane. In conventional airplanes, the
cabin is kept as small as possible to minimize drag. This restriction does not
apply to the FMX-5, which carries two people in a cockpit which measures 80
inches between the window sills. Each seat is 20 inches wide, and they are
separated by a center console, which houses the stick, and acts as a
fore-and aft systems tunnel for control linkages. There are windows in the floor
on each side of the cockpit. There is a large baggage compartment behind the
seats. A child seat can be installed in the baggage compartment.

A 15% scale
radio-controlled model of the FMX-5 has been built and extensively flown. It
flies well, and has flying qualities very similar to the models we flew during
the development of the single- seat Facetmobile. In particular, FMX-5 retains
the excellent high angle-of-attack controllability and departure resistance
shown by the Facetmobile (N117WD), both in model form and full scale. The model
could be routinely flown with full-aft stick, and remained controllable, with no
sign of a stall or spin tendency. A 1/16 scale model of the FMX-5 was tested in
the Cal Poly Pomona wind tunnel. The data taken confirm the configurations
docile aerodynamics, and also show a 40% improvement in L/D over the original
Facetmobile configuration.

FMX-5 Ultra High Altitude UAV:

While progress on the restoration of the original
Facetmobile, N117WD, has been extremely slow, other exciting things have been
happening in the Facetmobile World. For the past few years, an unmanned FMX-5
has been under development to return payloads from balloons flying at extremely
high (over 98,000 feet) altitudes. These FMX-5 based vehicles have been flying
since mid 2005. We have just now been given permission by our customer to reveal
a little about this program. Click on the picture to learn more about it.

In 2003, in partnership with the California Space Grant
Foundation we won a NASA contract to study the application of Facetmobile low
aspect ratio airplane concepts to the design of future Personal Air Vehicles.
The study examined building a low aspect ratio airplane like the one
pictured above using pre-cured composite sandwich panels cut on numerically
controlled machinery to form the major components of the airframe.

Conclusions
From The NASA PAV Study:

Flight
tests of the FMX-4 have shown that a faceted low aspect ratio all-lifting
airplane can have good flying qualities, compatible with a modest level of
pilot skill and be highly departure resistant.

A
faceted low aspect ratio all-lifting airplane can have performance
comparable or superior to a conventional airplane having the same power
carrying the same useful load.

Due
to its intrinsic structural efficiency, a low aspect ratio all-lifting
airplane will have an empty weight that is approximately 55% of that of a
conventional airplane having the same useful load and cruise performance.

The
low aspect ratio study airplane, with 80 horsepower has up-and-away
performance comparable to the current-generation all-metal trainers powered
by the 115 horsepower Lycoming O-235.It
is significantly superior to the conventional all-metal airplanes in terms
of takeoff distance and rate of climb.

The
overall system-level transport efficiency of the low aspect ratio study
airplane is significantly superior to the classical riveted all-metal
airplanes, and comparable to a modern, molded all-composite machine.

The
low aspect ratio all-lifting configuration composed of flat panels is well
suited to automated manufacture of components, and will require many fewer
hours to assemble than a conventional configuration.

The
flat-panel construction of the study configuration allows it to take
advantage of cost savings available from use of CNC high-speed machinery
without the need for the airframe manufacturer to purchase or maintain
expensive machinery or tooling. Large cost savings can be realized even at
low production rates.

The
non-recurring cost of tooling and specialized machinery required to
fabricate the parts for a faceted low aspect ratio all-lifting airplane and
assemble the airframe will be much lower than comparable costs for a
conventional wing-body-tail configuration.

Due to its combination of light weight,
compatibility with automated manufacture, and reduction in assembly labor
hours, a low aspect ratio all-lifting sport/trainer airplane similar to the
study configuration can cost up to 50% less than a conventional airplane
designed for the same mission.

This page was created by Lynne Wainfan All Rights Reserved. All images on
this page are Copyright Barnaby & Lynne Wainfan. No commercial use
is authorized. Cartoon courtesy KITPLANES Magazine. In-flight FMX-4 image is
copyright EAA, used by permission of EAA. Facetmobile image in logo and
background courtesy of Koen Van de Kerckhove.